Percussion tool for wave transmission apparatus



i ,1932. w. R. DEGENHARDT ET AL 1,857,624

PERCUSSION TOOL FOR WAVE TRANSMISSION APPARATUS Filed Feb. 28, 1928 Will" 90 percussion tool Patented May 10, 1932 UNITED STATES i WILLIAM. RUSEL DEGENPIARDT, or LONDON, A LAN FRED DE ERAINE; F WEMB'LEY, AND ROBERTHENRY BICKNELL, DECEASED, LATE OF WESTMINSTER, ENG AND, BY ROBERT ALAWIMBERLEY BIoKNELL, 0E .LoNDON; AND ARTHUR BIcKNELL, 0FBIRMINGHAIvL-ENGLAND, LEGAL REPRESENTATIVES 'oE ROBE T HENRY BICK- NELL,DECEASED, ASSIGNORS To THE ERANooIS oEMENT TIo GOM AN LIMITED, 013EoNoAsTER, ENGLAND, A BRITISH COMPA 4 Y I I PERcUSsIoN TooL PoR wAvE'TRANSMIssIoN APPARATUS This invention relates to percussion tools 7 foroperation by compressional liquid wave transmission mechanism and. moreparticularly to the spring suspension of the tool by the aid of a bodyofliquid,the compressibility of which under the rapid wave transmissiongives the necessary resiliency for the suspension. 1 In the suspensionof tools of this kind it is 11) necessary to obtain resonance betweenthe reciprocating mass and the resilient element. As is Well-known, inany spring suspension of a mass, if any predetermined natural I periodof oscillation is to be obtained, the re- 16 siliency or capacity of thespring suspension must bear a definite relation to the reciproeatingmass which is supported and the greater the mass the more rigid must bethe resilient support. For substantial masses and high 80 periodicity ofoscillation the yield of the spring suspension for a given force must besmall and the compressibility of a. volume of liquid is sufiicient, inthe case of aconsiderable reciprocating mass, to bring the naturalperiod of the suspension sufficiently low to correspond to theperiodicity of the wave transmission, so that resonance is establishedforfthis periodicity.

The use of li uid as a resilient body in a the liquid being divided intotwo volumes on opposite sides of a dividing wall belonging to the bodyof the tool, but according to the which-resonance depends is composed ofa single body or column of liquid. Through this body or column of liquidextends the percussion orstriking device or rod and according to afurther feature of the invention this rod is not directly acted upon bythe wave transmission, but an intermediate striking member is providedon which the wave transmission liquid operates. .This intermediatemember, which is preferably in the form of a sleevemounted on thepercussion rod, meets towards the end of itsstroke a collar orprojection on the rod and delivers the blow to the rod and thence to anypercussion device which it is designed to operate; A portion of the saidsleeve is disposed within a chamber conas already been proposed, 7 infront of the working chamber (1;; I

present inventionthe resilient element on Application filed February 28,1928, Serial'No. 257,768, and in Great Britain Mar-ch25, 1927. I I

taining the aforesaid single body or column of liquid and is soform'edthat after a forward stroke has been"given,-i the sleeve isforcedback on the return wave against the operating wave-transmissionliquid J by the pressure in the said chamber, ready for the next forwardstroke. i c l In order that thesaid invention may be clearly understoodand readily carried into effect, the same will now be more fullydescribed with referencetothe accompanying drawings in wh1ch:-; V

Figure 1 is an 'axlal section of one form of percussion toolconstructed'according to this 1 invention, and. l

Figure 2 is an ax ial section of another form. of percussion toolconstructed according to this invention. w q

In both of the constructions shown A is the body or casing of the tool,B is the percussion rod which is arranged centrally within' the bodyA-and passes through glands A A at the rear andforward ends of the toolbody,

C'is the workingchamberlto whichthe'opel I ating wave-transmissionliquid is admitted by means ofa pipe C and -D isthe aforesaid chambercontainingthe single body of liquid (hereintermed-':the liquid springChamber) situated inthe forward part of the tool'body Referring toFigurel Eis the" aforesaid intermediate striking member inthe form ofasleeve surrounding the percussion rod B. This sleeve passes through abushing E of substantial length at the middle portion of the tool,inwhich bushingvit has a close. sliding fit, the'sleevealso having a closesliding fitup'on'the percussion rod B; Thefor- Ward end of'the sleeve E.is providedwith a head E forming at'the rear a shoulder the surfaceof'which'isof smaller area than the forward end of the headyowing to thethickness'of the sleeve ,itself,; so that the head forms a differential"piston and the pressure in the liquidspring chamber Din which the headis situated tends to drive back the sleeve.

The rearend of'the sleeve is openpto the Working chamberC to which thewave-transmission liquid'is supplied so thattheWave motion transmittedthrough the: liquid acts upon the rear end of the sleeve E and duringthe forward half of the wave this. sleeve is forcedforward at highvelocity, increasing from the beginning of the Wave and compressing, theliquid inthe spring. chamber.

'.At about the point of. maximum velocity the head of the sleeve strikesa thick collar B on.

the percussion rod and the blow is delivered to ya percussion portion ofthe tool suitable for any desired type of operation such. as percussiondrilling. Following upon the delivery of the blow the compressed liquidin the liquid spring chamber D begins to return the: sleeve Evv andduringthe succeeding half wave,' when the pressure of thewavetransmission liquid falls to its minimum,' the sleeve returns to itsinitial position ready for the next stroke, which begins when: thecompression ha'l'tt of the wave starts. The forward movements of the rod13' are limited by the collarB 'whiclm comes against the rear end of abushing A ein which the front part 7 of the said rod slides, and therearward movements ofthe sleeve E- are limited by its head E which'comes against the front end of the atoresaid bushing p I As thesleeve E must be free to slide readily over the contacting surfaces andthere are during eachoscil'lation considerable differences of pressurebetweenthe liquid spring chamber D and the working chamber Crecei'vingthe operating wave-transmission liquid, leakage is liable tooccur froirn'the work ing chamber intothe liquid spring chamber and toprevent an undesirable accumulation of pressure in the latter chamber'we may provide as shown a relief valve F which opens; at apredetermined pressure. The said relief valve F would beset to open atabout the mean pressure in the working chamber C. This relief valveforms the subject of our Uru' ted States Patent No. 1,771,672, BritishPatent application No. 8,281 of 1927,. now Patent No. 293i,088,-a':ndmay beE-replaced by any of the equivalent devices mentioned in thespecification of that application. ,The s r spring controlled reliefvalve 6 similar to the relief valve F. A screw-down valve G may also beprovided for controllingthe flow otliquid from the working chamber C tothe liquid spring chamber D through a passage A in the tool body. Thisvalve is opened when the tool is to be started work-- ing so as toenable the'chamber D to be filled with liquid is closed during normalworking; it can, howeverjbe partly opened to any desired extent duringworking, so as to vary the force of the blow of the sleeve E upon thecollar B oftl ie percussion rod B. V

With a single resilient body of liquidiin the chamber D and anintermediate striker or sleeve E as above described, there is relative-1y small wear upon-the packings of the permission rod B as its-movement'is. confined tic-u of t roundin said rod withrelative lonitudinal 3 63 may be provided, as showmvvith a to the small movement ofthe blow, while the relatively large reciprocating movement given by thewave-transmission is taken up by the said sleeve which has'a longbearing surface and does not require packing as both ends of the sleeve.areiin liquid;

The construction shown by Figure 2 is similar to that shown by Figure 1except for the omission of the sleeve E and the consequent alteration inthe percussion rod B, similar parts being indicated 'by the samereference letters, in the two figures. As a result of the omission ofthe sleeve Ethe middle portion B of therod- Bthatis situated in thebushing E is made of larger diameter t'l ian the rear portionof therodto provide an area for cheep-erecting liquid in e the working chamber Ctov act upon the required area for the liquid in the chamber D to actupon in orderto. move the rod rearward-s is provided by making frontporhe rod: of smaller diameter than the middle portion as shown. Acollar B lS13'1 0. vided' for limiting the rearward movements of the rodB, andthetorward movements areni limited: by the sheuld erfbetween the:larger (dd'SJILGU-XFPQItlOB and the smaller diameter front portion ofthe rod, saidcollarand shoulder comi'n 'against the bushings and Arespectively. \Vhat we claim and, desire to secure-by Lettors: Patent ofthe United States is-:-"

In a percussion tool tor operation by compressional liquid wave-transmmechanism,,the combination with apercussio i3 rod and a working chamberof a sleeve su-rmovement them, 0 e end of s d sleeve being in contactwith 4 liquid chamber, and a chamber containing a s g body of liquid. inwhich the other end of saie sleeve is disposed, said sleeve being sovconstructed that after a forward stroke hjasbeen performed it is movedback by the pr of the liquid in the secondmentioned her ready for thenext forward stroke 2. In a percussion tool for operat compressionalliquid wave-tra sr i-neehan-ism' the combination with. i, A we mentsclaimedin claim 1, of relief valve for 31 ,th single body of-liquid. 1"3. In a percussion tool for openationby compressional liquid waveeri nmechan sm, the combination with moi claimed in claim Lot a-conve tweenthe working chamber and the chain ber ontaining the single of liquid anclj-,11-stable: valve controlling this con-fl WILLIAMRUSSELL'DEGENHA'RDT.

AL-LAN FREDA: FRA HE- ROBERT ALAN. WIMBERLEY'BICKNELL; ARTHUR mcxum, VAdministrators for Robert H emry BicilmeZL- Deceased.

